Specific Energy Converter
Convert energy per mass between J/kg, Wh/kg, Btu/lb and thermochemical calorie units.
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Result
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Calculation steps
Work through one step at a time or reveal the complete calculation. The steps use your current inputs.
How to calculate
Convert numerator energy to joules and denominator mass to kilograms.
Specific energy in J/kg=value×joules per energy unit/kg per mass unit
Worked example
1 Btu(IT)/lb equals 2.326 kJ/kg. One Wh/kg is 3.6 kJ/kg.
Assumptions and input details
Specific energy means energy divided by mass. Both mass and energy must describe the same stated sample or storage basis. The international avoirdupois pound is 0.45359237 kg. Btu(IT) and cal(th) retain their explicit definitions. No heating value, moisture basis, battery usable fraction or energy-per-volume density is assumed.
References: NIST: unit conversion factors
Using this calculator
Can I enter my own problem?
Yes. Replace the example values with your own inputs. The result, calculation steps, tables and applicable diagrams update from those inputs. Blank or invalid values clear the result; example values are never silently substituted for missing inputs.
Are the results exact?
Results use floating-point arithmetic and displayed rounding. Read the formula, assumptions and any stated data precision before interpreting the result.
Is my input uploaded?
The calculation runs in your browser. No account, file upload or external AI service is required. Inputs are not saved between page reloads.
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